Unlike some prior art, the instant invention does not comprise a static tensor of multitudinous lights but rather comprises dynamic movement of a relatively small number of lights for such a volume. This invention is a volumetric, stage-type three-dimensional image display device. It overcomes many problems associated with prior three-dimensional image display devices. The most notable of the problems that this device overcomes include the inability to produce opaque objects and the high cost generally associated with three-dimensional displays. These two problems are overcome while still maintaining other features that many three-dimensional displays do not have. These other features include the ability to produce images that can be viewed with a large degree of freedom of viewpoint and the fact that the viewer does not need to wear any sort of filters or displays over the eyes.
The device is a stage-type volumetric three-dimensional display. It produces images by having a relatively small number of small light producing devices move extremely rapidly and pass through the entire volume of a space that is cylindrical, or spherical (depending on the embodiment in question). By passing through the entire volume, the lights, when controlled properly, are able make any point in the space appear to glow, by emitting light only while occupying the area that is intended to glow. By having the light producing devices sweep through the entire display volume within the refresh time of the human eye, multiple points are made to appear to glow simultaneously. By properly controlling these glows, perceived entire three-dimensional images are formed within this space. The glows appear as an actual image because the lights are moving fast enough for the phenomenon of xe2x80x9cpersistence of visionxe2x80x9d to cause all the separate glows (and associated period of glow for each light) to seem as if they are occurring simultaneously to the human eye. To facilitate understanding, consider an example in which the display is of a three-dimensional, wire-frame image of a two-drawer filing cabinet. Also, suppose that the light producing devices start at the bottom of the display volume (suppose a cylindrical volume) and they move to the top of the volume in such a way as to have at least one light pass through nearly every point in the display volume. Please recall that this is done within the refresh time of the human eye. FIG. 0-A shows the image of the filing cabinet at approximately 25% completion; that is, after the lights have passed through the bottom 25% of the display volume. The numbers in FIG. 0-A represent individual bursts of light, exaggerated in size to make the drawing more understandable; the value of the numbers represents how recently the burst of light was produced, so higher numbers represent more recently produced bursts of light. Recall that these bursts are produced by the lights as they pass through the volume. The cylinder shown represents the display volume; the hidden line of which is shown as dotted. FIG. 0-B shows the filing cabinet image at the point in time when the lights have thus far passed through the volume from the bottom of the display volume to 50% of the way up the display volume, effectively generating 50% of the filing cabinet image. FIGS. 0-C and 0-D show the same thing as FIG. 0-B, but at 75% and 100% completion, respectively.
This display (depending on the embodiment used) has the ability to produce images that appear as opaque. This is done by having the light from each light burst sent in only certain directions, such that a viewer coming from that direction should see that light burst. This is explained in detail shortly.
One central advantage of this method of producing three-dimensional images is due to the simplicity of the actual light generating system, which consists of no more than several strings of lights (if the ability to produce opaque images is being implemented, the lights need to be able to control the direction(s) in which they emit light for a reason that is explained shortly). The result of that is that the display has a manufacturing and, as a result, retail cost that is low enough for the display to have an inherent real-world advantage over other three-dimensional displays.
The second central advantage of this invention over other three-dimensional displays is that the images produced by this invention (if the feature is implemented) appear opaque (as if hidden line removal is performed for all viewpoints). Specifically, that means that only the face of the image that is closest to the viewer is visible to that viewer. For example, if a ball is being displayed without this ability, both the front and rear (relative to the viewer) faces of the ball are visible. This invention has the ability to allow the viewer to always just see the face of the image closest to the viewer, without respect to the angle from which the viewer is looking at the display. The closest face is always shown. Because this feature is accomplished without the need for the display to electronically track the location of the head of the viewer, multiple viewers, all at different viewpoints, can look at the image at once, and each viewer only sees the face closest to him or her. To understand how this is done, suppose that the same image of a filing cabinet with two drawers is to be displayed again, but now, such that it appears opaque. As with the earlier example, the light producing devices move from the bottom of the display volume to the top in such a way as to pass through nearly all of the volume in the process. As with the earlier example, the exact means by which this is done does not matter yet, suffice it to say that nearly every point in the volume is passed through by at least one lightxe2x80x94and this is done in less than the refresh time of the human eye. In this example situation, unlike in the earlier example, the individual light producing devices are able to send light in only selective directions; that is, a light producing device may be controlled in real time so as to send light only up, or only left, or only up, right, and left, etc. Now, when the bursts of light that produce the image of the filing cabinet are generated, the light emitted to form each of the points that compose the image may be sent in only some directions, as opposed to all directions. Actually, the directions in which the lights are instructed to send light are very precisely controlled, and the direction(s) in which any particular light emitting device is instructed to send light when producing a certain point of light is determined as follows: any point that composes the filing cabinet image (if the cabinet is intended to be opaque) ought to not be visible from certain viewpoints; specifically, those viewpoints from which, some other part of the filing cabinet is obscuring the point in question. Since it is now known the viewpoints from which the point should not be visible, the viewpoints from which the point should be visible are, simply, all of the remaining viewpoints. The directions that correspond to these remaining viewpoints are the directions in which light is sent when this point in question is produced. This is shown in FIGS. 0-E through 0-H; which show the image of the filing cabinet being generated at 25%, 50%, 75%, and 100%, respectively. In FIGS. 0-E through 0-H, unlike in FIGS. 0-A through 0-D, when a light emitting device produces a point that composes the filing cabinet, the light is sent only in the previously described directions. Thus, the points seen in FIG. 0-H are only those that should be seen from the point of view used in FIG. 0-H; if a different viewpoint were used in FIG. 0-H, different points would appear to be active, points that would be correct for that viewpoint. All the same points in the display volume in which light was emitted without the opacity function still have light emitted with the opacity function except that with the opacity function, light is only being sent in selective directions. This is shown in FIG. 0-I, in which numbers that are filled black represent points from which light is directed toward a viewer viewing the display volume from the viewpoint used in FIG. 0-I. The numbers that are white with a black outline represent points from which light is sent in other directions, and thus is not visible from the point of view used in FIG. 0-I. What this does is it causes the points that are visible from any particular view point to be those points thatxe2x80x94if the filing cabinet were realxe2x80x94would be unobstructed by other parts of the filing cabinet from that point of view. Since the locations in the display volume from which light appears to be emanating can be made to appear to be different depending on view-point, viewers at various locations with respect to the display volume can all be shown a different three-dimensional image. Specifically, the image that each viewer is shown is the one composed of the points of light needed to make the object that is being shown appear to be opaque from that viewer""s point of view. Put another way, each viewer sees only the face of the image closest to him or her, but not the face that is rear with respect to that viewer. The result is the illusion of opacity, and the more precisely the directions to which the light producing devices emit light can be controlled, the better the effect of opacity. The way in which the controlling computer determines how to control the lights so as to produce opaque images is a complex, lengthy process, and is explained in the detailed description.
This display consists of several key systems:
The light string or strings; each of which consists of several hundred small lights. Each light (if the opacity feature is being implemented) is able to control the directions that it sends light. This (depending on the embodiment used) requires the direction-controlling light to consist of several smaller lights. If the opacity feature is not being implemented, then the lights send light in all (or as many as possible) directions at once, except the bottom.
The mechanical system that moves the light string or strings. This system is used to move the light string(s) in the proper pattern to produce the needed two levels of dimensional extrusion; that is, going from a 1-dimensional light string to a three dimensional image. This consists of no less than two distinct movementsxe2x80x94for example, one movement might be an up-down oscillation, and the second might be a front-back oscillation. What this accomplishes is to essentially xe2x80x9cextrudexe2x80x9d the one-dimensional light string into a two dimensional surface, which is then extruded to a three-dimensional volume. A complete motion cyclexe2x80x94that is, having nearly every point in the display volume have at least one light pass through itxe2x80x94is completed within the refresh time of the human eye.
Encoding software is needed to take an original three dimensional image stored on a computer and convert it to a collection of sequential streams of information that are sent to a set of decoding electronics in the display which then send appropriate derivative streams of data to the physical lighting elements.
Decoding electronics are used to convert the encoded image coming from the computer into activation and deactivation sequences for the individual lights on the string(s). The decoding electronics are actually attached to the light string(s) and convert the low band-width, high speed data streams that come from the computer into actual instructions for each light.
All of these parts function together to take a three dimensional image stored in a computer and display it inside of a display volume, the shape of which varies with embodiment.
The lights themselves, to be able to control the direction that they send light, are composed (depending on embodiment) of a plurality of smaller lights, each of which has a very narrow viewing angle. Each of these smaller sub-elements are able to activate and deactivate extremely rapidly. In one embodiment, these sub-elements are very small light emitting diode chips. However, in alternate embodiments, any item that is very small and produces a reasonably bright light, that is also easily visible even while the light is rapidly moving, that also has a very short activation and deactivation time, is sufficient to be used instead.
The instant invention involves stage-type three-dimensional displays that employ moving light producing devices. There is not a very large amount of known prior art in this field. One example, though, is contained in U.S. Pat. No. 5,663,740. In that patent, a three dimensional display is discussed in which there is a moving, multi-dimensional matrix of lights. Specifically, a two-dimensional matrix of lights is attached to a moving support structure. The matrix is moved back and fourth rapidly enough to be a blur to a human eyexe2x80x94and thus be able to make any collection of points in a three dimensional volume appear to emit light simultaneously. There is also another embodiment of interest in said patent in which a spiral shaped screen covered with lights (essentially a twisted, two-dimensional matrix of lights) rotates about its central axis faster than the human eye can detect. This, again, allows for any point or points in a cylindrical volume to appear to emit light simultaneously to the human eye.
Initially, these embodiments may seem close to the instant invention. However, there are extremely serious differences. First of all, said prior art requires a two-dimensional matrix of lights in its embodiments. This means that for a modest pixel resolution in the matrix of 640 by 480 pixels, a total of 307,200 light emitting elements are needed. This contributes substantially to the cost of the display. The instant invention requires only from one to several one-dimensional strings of light producing devices. If each string has one thousand light producing devices, and there are ten strings (a liberal number), then a total of only 10,000 light producing elements are needed. The cost savings is extremely substantial.
To accomplish the needed result with so far fewer light producing elements, the instant invention uses at least dual sets of cooperating motion to pass through a substantial amount of the desired volume. For example, a string of lights may move back and fourth (opposing the view) repeatedly (faster than the refresh time of the human eye), while moving left and right much faster still. Thus, nearly the same volume may be covered as in the ""740 patent, but with far fewer light producing elements required. One might contend that this added mechanical complexity makes moot the advantages of needing fewer light producing elements. This is believed not to be the case. First of all, the added mechanics do not have to be particularly complex; and its added cost is substantially less than the cost of the magnitudes-greater number of light producing elements required for the ""740 disclosure.
In addition, the instant invention includes the capacity to produce opaque images, an ability the prior art reference does not include. One might contend that the similarities between the two inventions would make the opacity system as employable in the prior art patent as it is in the instant invention. This is not the case.
Before explaining exactly why this is true, it might be best to begin with a brief explanation of how opaque images are formed in the instant invention. First of all, one must consider how a non-opaque image is formed by this invention (or by the ""740 patent). To form an image, a series of lights is moved in some such way as to have nearly every point in a volume passed through by at least one light producing device within the refresh time of the human eye. Images are produced by emitting numerous bursts of light that, when seen together, appear to form three-dimensional images. The light producing devices that produce the bursts of light are preferably omni-directional, so that a viewer from as wide a range of view points as possible is able to see the points of light that are produced-and thus the resulting image. How could these images, though, be made to appear to have opaque portions?. The answer is to eliminate the omni-directional lights. In the real world, when viewing a physical, opaque object, two viewers standing at different viewpoints with respect to the object being viewed see two different images. One person sees an image of the object from one point of view; and the other person sees an image of the object from a second point of view. Suppose that the exterior of the object (the part that is potentially visible) is thought of as a collection of points; even though one can see only part of the outside of the object at any one time, again, suppose that the entire exterior is composed of points. If this real, physical object is thought of in this manner, it is obvious that all the points are always there, but one viewer only sees some of themxe2x80x94since the rest are obscured by the ones that the viewer does see. Thus, any viewer looking at the object only sees some of these points. Although the preceding was just a modified way to think of opacity in the physical world, it shows a good way to generate the effect of opacity with the instant invention. Ideally, the points of light that compose the three-dimensional images would be able to block one-another, like matter, and thus a viewer would only see the points of light (which compose the image) that are closer to him or herxe2x80x94thus producing opacity. However, we can not do this, but we can attempt to artificially accomplish the same effect, by using light producing devices that dynamically control the directions in which they emit light; that is, a light producing device may be controlled so as to emit light in many directions, just up, just left, etc. Now, whenever a burst of light is produced for an image, the light of the burst is sent only in the directions of viewpoints from which this burst of light should be seen. In other words, if a burst of light is produced that makes up part of the left side of an object, the light of that burst will only be sent left, since a viewer on the right should not be able to see the left side of the object! If this process is followed for every point of the image that is produced, the image will appear to be opaque.
This begs the question of how light producing devices can be made that can be controlled in real time as to what direction(s) they send light. The answer is to make each light producing device a combination of several smaller light producing devices. An example of this is shown in FIG. 51. In FIG. 51, the small squares (one of which is 181) are tiny light producing devices, such as LED chips. These tiny light producing devices (one of which is 181) are laid on a sphere 182; such that the plane of each tiny light producing device (one of which is 181) is perpendicular to the normal of the sphere 182 at the point at which the tiny light producing (one of which is 181) device is located. This causes each tiny light producing device (one of which is 181) to each face and emit light in a different direction. If these light producing devices (one of which is 181) are controlled individually, that which they form is essentially a light producing device that can be dynamically controlled as to which direction(s) it sends light.
This is where the instant invention has a substantial advantage over the prior art. The instant invention, to produce opacity, only requires several thousand (to be liberal with the estimate) direction-controllable light producing devices. If there are 10 strings in use, and each string has 1000 direction-controllable light producing devices, and each direction-controllable light producing device is composed of 10 tiny lights, a total of 100,000 tiny light producing devices are needed. If the opacity concept were to be implemented in the prior art, it would require an enormous amount of light producing devices. Suppose the prior art is being implemented with a matrix of 640 by 480 direction-controlling light producing devices, again with 10 tiny light producing devices per direction-controlling light producing device. Then a total of 3,072,000 tiny light producing devices are needed! It quickly becomes very impractical for the opacity concept to be implemented in the prior art.
In addition, there is another difficulty in implementing the opacity concept in the prior art. This problem, again, rests with the very nature of a two-dimensional matrix. In a matrix, suppose a particular direction-controlling light producing device is sending light in a direction such that the rest of the matrix blocks the light. This would cause a point to potentially become invisiblexe2x80x94if that one burst of light is the only time it is supposed to be seen. The matrix itselfxe2x80x94even if the matrix is spiral shaped as in one embodiment of the ""740 patentxe2x80x94tends to block out other parts of the matrix. It is true that a string does this as well, but to a much lesser extent, because a string can only obscure part of itself in one dimension, a matrix can do so in two! This is one of the main problems with a matrix, and it becomes much less of a problem with one or even several properly positioned one-dimensional strings of light producing devices.
In addition, moving a matrix such as disclosed in the ""740 patent through a volume at a great speed will encounter a great deal of air resistance. To alleviate this, the matrix may be enclosed in a vacuum, but this adds new complexity, and can greatly increase the difficulty in repairing the device should it need repairs. These problems are not inherent to a display that uses a system of one-dimensional string(s) of lights as in the instant invention instead of a matrix as in the ""740 patent, because a string will encounter much less air resistance due to its linearity.
There are numerous other patents in existence that are sufficiently similar to the ""740 patent that they need no individual explanation regarding the distinction between them and the instant invention. Examples of such patents include U.S. Pat. No. 3,154,636 by Shwertz; U.S. Pat. No. 6,115,006 by Brotz; and U.S. Pat. No. 5,748,157 by Eason. The work by Eason includes a lot of work with 2-dimensional image production, and one three-dimensional image production device. This three-dimensional image producing device (shown in FIG. 14 of said patent), however, is still differentiated from the instant invention due to the reasons given for the ""740 patent. Further patents that are differentiated from the instant invention for the same reasons discussed earlier include U.S. Pat. No. 5,596,340 by Otomi; U.S. Pat. No. 5,057,827 by Nobile et. al which presents several methods of displaying essentially two-dimensional, curved images in addition to a method for displaying three-dimensional images in FIG. 5 of said patent. Although different in shape from the matrices of other art, this patent still contains a matrix of light producing devices, and one axis of rotation, and so is differentiated from the instant invention for essentially the same reasons given earlier for the ""740 patent. Further similar art includes U.S. Pat. No. 4,160,973 by Berlin, Jr. Again, the common idea among these pieces of prior art is that they employ a moving two-dimensional matrix of points of light to produce three-dimensional images. This is the chief distinction between these examples of prior art and the instant invention, which uses from one to several moving one-dimensional strings of lights to produce a three-dimensional image. Other prior art that tends to use a projection based image production techniques include U.S. Pat. No. 6,064,423 by Geng; U.S. Pat. No. 6,054,817 by Blundell; U.S. Pat. No. 6,052,100 by Soltan et al.; U.S. Pat. No. 5,954,414 by Tsao; U.S. Pat. No. 5,854,613 by Soltan et al.; U.S. Pat. No. 5,754,147 by Tsao et al.; U.S. Pat. No. 5,162,787 by Thompson et al.; and U.S. Pat. No. 4,983,031 by Solomon. Since some or all of these employ projection in at least one embodiment, the projection alone differentiates these from the instant inventionxe2x80x94which does not use projected images, as it is of the stage type.